Question

c. If only 43.8 g of nitric acid is obtained from the reaction, calculate th. molecules Cl2 and atoms of Cl. 8. 42.0 g Cl2 contains A) 1.18; 0.592 B) 3.57x 1023; 7.13 x 1023 C) 3.57 x 1023: 1.78 x 1023 D) 1.78 x 1023; 3.57 x 1023 E) 0.592; 1.18 9. How much Ca(NO3)2 should be weighed out to have 0.650 mol? A) 66.4 g B) 97.6 g 107

Answer 1

8)

Molar mass of Cl2 = 70.9 g/mol

mass(Cl2)= 42.0 g

use:

number of mol of Cl2,

n = mass of Cl2/molar mass of Cl2

=(42 g)/(70.9 g/mol)

= 0.5924 mol

use:

number of molecules = number of mol * Avogadro’s number

number of molecules = 0.5924 * 6.022*10^23 molecules

number of molecules = 3.567*10^23 molecules

1 Cl2 molecule has 2 atoms of Cl

So,

Number of Cl = 2*number of molecules of Cl2

= 2*3.567*10^23

= 7.13*10^23 atoms

Answer: B